In a machine tool, a thermal displacement correcting method for correcting a machining dimensional error caused by surrounding room temperature variation or cutting heat is often used. The method is configured such that a temperature sensor such as a thermocouple or thermistor is provided on each of components of the machine tool, temperature information from the temperature sensor is obtained by means of use of a temperature measuring device such as a voltmeter or ammeter, a thermal displacement amount is estimated from the obtained temperature information to calculate a correction amount for a moving body such as a main spindle or tool rest, and the moving body is controlled based on the correction amount (see Patent documents 1 to 3).
[Patent document 1] Japanese Patent Publication No. 1986-59860
[Patent document 2] Japanese Patent Publication No. 1994-61674
[Patent document 3] Japanese Unexamined Patent Publication No. 2001-341049